The field of the invention is push-back storage systems.
Push-back cart storage systems typically use rolling carts for carrying pallets or other cargo, on slightly inclined rails. By providing several carts on a set of rails, useable space between aisles in e.g., a warehouse, is increased as multiple pallets can be stored and retrieved from a single aisle. Consequently, aisle space necessary in conventional storage racks for forklift access may be used for additional storage racks, providing more efficient use of space.
With the present push back cart systems, the first pallet is placed on the first rolling cart by a forklift. The forklift then pushes the pallet along with the first cart so that the second cart can receive a pallet. Ideally, the second cart will be fully exposed so that it can receive a pallet. However, because the first cart""s rollers roll along rails in the second cart, a frictional force is created by the rollers which tends to move the second cart along with the first cart. As a result of this movement, the second cart is not fully exposed and cannot receive a pallet. In cart systems having more than two carts, the same unwanted movement occurs in the other carts as they are subsequently loaded.
Although various push-back cart storage systems have been used in the past, there is a need for an improved system which prevents this unwanted movement of the cart immediately underneath the cart that is currently being loaded and pushed back.
To these ends, the present push-back cart storage system includes a pair of spaced apart support rails. An outer or first cart has wheels which roll on the support rails. The outer cart has side members and a middle or second cart has front wheels which roll on the side members of the outer cart. Rear wheels on the middle cart roll directly on the support rails. For a four deep system, an inner cart may be provided with front wheels rolling on side members of the middle cart, and with rear wheels of the inner cart rolling directly on the support rails.
A latching mechanism in a push-back cart storage system has a latch preferably mounted to cross members which are mounted to the support rails of the push back cart storage system.
In the preferred embodiment, the latching mechanism comprises a pair of spaced apart spring members mounted to cross members. Each spring member advantageously includes of a pair of spring plates mounted between the cross members. The carts are held in place by the engaged first spring plates until the loaded first cart reaches its rearmost position relative to the second cart. Once the first cart reaches that position, the front cross member on the second cart releases the first pair of spaced apart spring plates. The release is caused by the force of the forklift, which, in moving the second pallet into the pallet bay for ultimate placement onto the second cart, continues to push the first pallet rearwardly even after the first cart is in its rearmost position relative to the second cart. This rearward movement of the first pallet causes the front cross member of the second cart to push against the first pair of spring plates causing them to deflect downward and release the second cart so that it can move in the rearward direction. As the forklift continues to push the first pallet rearwardly, the front cross member of the second cart then pushes against the second pair of spring plates, causing them to deflect downward and release the second cart so that it can continue to move rearwardly until it reaches the rearmost position relative to the third cart.
Of course, in addition to this spring latch, various other mechanical equivalents, such as detent mechanisms, bump ramps, magnetic holding elements, may be used with the scope of the invention, to hold the carts in position while loading.
Accordingly, it is an object of the invention to provide an improved push-back cart storage system. Other and further objects and advantages will appear hereinafter.